I wouldnt see the point...I mean, why would you need such a high speed bus on the second graphics card, considering that the primary is the only one that will be used, for having a few extra monitors about. a PCI slot is more than enough
but someone did ask about dual AGP slot motherboards here a few months back and I think they did say about one - do a forum search it will be there somewhere
Already, some games are problematic w/ATI, while sympatico w/Nvidia, or vice versa if you wish, & at more than just the driver level. So, if in the future games are going to be 'optimized' for one brand vid card or the other, then why not a mobo supporting 2 agp vid card solutions? Toggle on/off via bios & away you go.
That idea would involve a lot of extra $$ in the design and manufacture of a motherboard. It's not worth it for the few people that might actually use it now and then. Plus, the more variables you through into the system the more likely you are to have incompatiblilty and stability issues.